list (list<>::cbegin()): Use C++11 direct initialization.

list (list<>::cbegin()): Use C++11 direct initialization.

2018-10-08  François Dumont  <fdumont@gcc.gnu.org>

	* include/debug/list (list<>::cbegin()): Use C++11 direct
	initialization.
	(list<>::cend()): Likewise.
	(list<>::emplace<>(const_iterator, _Args&&...)): Likewise.
	(list<>::insert(const_iterator, initializer_list<>)): Likewise.
	(list<>::insert(const_iterator, size_type, const _Tp&)): Likewise.
	(list<>::erase(const_iterator, const_iterator)): Ensure consistent
	iterator comparisons.
	(list<>::splice(const_iterator, list&&, const_iterator,
	const_iterator)): Likewise.

From-SVN: r264911